Process for making alpha-chloro sulfides

ABSTRACT

Alpha -Chloro sulfides are made by the reaction of dichloromethyl ethers with the appropriate sulfoxide. The reaction is illustrated as follows:

O Umted States Patent [191 [111 3,890,394

Kuhn June 17, 1975 PROCESS FOR MAKING ALPHA-CHLORO SULFIDES PrimaryExaminer-Lewis Gotts Assistant ExaminerD. R. Phillips [75] Inventor2:22;: Kuhn Sarma Omano Attorney, Agent, or FirmChessie E. Rehberg [73]Assignee: The Dow Chemical Company, [57] ABSTRACT Mldland Mlch' a-Chlorosulfides are made by the reaction of dichlor- [22] Fil d; A 28, 1972 omethyl ethers with the appropriate sulfoxide. The re- A l N 248 666action 18 illustrated as follows:

0.: pp Cl-lCl OCl-l -l-CH S(O)CH CH ClSCH +l-l- COOCH +HCI [52] 260/609260/488 The sulfoxide used must have at least one a-H. The [51] Int ClC07c 149/10 C07c l49/30 dichloromethyl ether is preferably one of lowmolecu- C07C 69/04 lar weight and such that the formate ester derivedfrom it has a boiling point substantially different from [58] Field ofSearch 260/496, 609 R, 609 E that of the wchlom Sulfide.

56 References Ci d The reaction proceeds conveniently at 0lO0C. and

OTHER PUBLICATIONS Taylor, Advances in Organic Chemistry, Vol. 6, pgs.343-345.

produces high yields in a short time.

10 Claims, No Drawings PROCESS FOR MAKING ALPHA-CHLORO SULFIDESBACKGROUND OFv THE INVENTION oz-Chloro sulfides are a well known familyof compounds having various uses. They have heretofore been made bychlorinating the sulfide with sulfuryl chloride or by the reaction ofthe corresponding sulfoxides with thionyl chloride [see, for example,Bordwell and Pitt, 1. Am. Chem. Soc., 77, 572 (1955)].

The dichloromethyl ethers used as reactants in the present invention arealso well known and can be conveniently made by the reaction of PCl onthe corresponding formate ester by the method of Gross et al., Org.Syn., 47, 47 (1967):

I-ICOOR PCl CHCI OR POCl Since the formate ester is regenerated in theprocess, it can be recycled indefinitely.

SUMMARY OF THE INVENTION According to the invention, a-chloro sulfidesare made by the reaction of the appropriate sulfoxide with adichloromethyl ether. The sulfoxide, of course, must have at least onea-l-l. The reaction can be illustrated as follows:

wherein R and R are each an organic group that is inert in the processand R and R are each H or an organic group that is inert in the process.The preferred inert organic groups are hydrocarbon, particularly alkyl,aralkyl or aryl.

The reaction is suitably conducted under mild conditions, such as about0-100C. for a time of a few min-. utes to a few hours, and preferably inan inert solvent.

Suitable solvents include aliphatic and aromatic hydrocarbons andhalohydrocarbons, the liquid chlorinated methanes and ethanes, and thelike.

DETAILED DESCRIPTION OF THE INVENTION In carrying out the process of theinvention, the reactants are contacted, preferably in an inert solvent,at a mild temperature, preferably about -50C., until substantialreaction has occurred. The desired product is then separated from thereaction mixture by any suitable means, preferably by distillationexcept highboiling or heat-sensitive products which may be moresatisfactorily separated by crystallization, solvent extraction, orother conventional means.

If separation of the product by distillation is desired, thedichloromethyl ether should be chosen such that the by-product esterderived therefrom has a boiling point substantially different from theboiling point of the sulfide product.

The ratio of reactants is not critical, though best results are obtainedwith substantially equivalent amounts of the reactants.

In those instances where the sulfoxide has at least one hydrogen atom oneach a-carbon atom, some of each of the two possible a-chloro sulfidesmay be formed, though in general the chlorine goes predominantly to thea-carbon atom bearing fewest hydrogen atoms.

The practice of the invention is illustrated by the following examples.

LII

EXAMPLE 1 Chloromethyl Methyl Sulfide One-half mole each of dimethylsulfoxide and dichloromethyl methyl ether were dissolved in 250 ml. ofchloroform at room temperature. A mildly exothermic reaction occurred.After 10 minutes, the mixture was heated to boiling and refluxed 15minutes. The solvent and the by-product methyl formate were thendistilled at atmospheric pressure, leaving the crude product insubstantially quantitative yield. This product was then distilled underreduced pressure to produce the purified product in 97% yield.

EXAMPLE 2 a-Chlorobenzyl Methyl Sulfide One-quarter mole each of benzylmethyl sulfoxide and dichloromethyl n-butyl ether were dissolved in 199ml. of chloroform and the mixture was refluxed 30 minutes. The solventwas distilled at atmospheric pressure, after which the by-productn-butyl formate and the desired product were distilled under reducedpressure. The product distilled at l09-l 10C. (0.8 mm.). Yield, 96%.

EXAMPLE 3 Chloromethyl Phenyl Sulfide By essentially the procedure ofthe previous examples, methyl phenyl sulfoxide was reacted withdichloromethyl B-chloroethyl ether. B.P., 93C. (6 mm.). Yield, 93%.

The following table shows other similar a-chloro sulfides that areproduced by the reaction of the sulfoxide with an a,a-dichloroalkylether. In the table, the reactants and products are defined by theradicals R as set forth in the equation above.

1. The process of making an a-chloro sulfide comprising reacting bycontacting the corresponding sulfoxide with a dichloromethyl ether.

2. The process of claim 1 wherein the reaction is conducted at about0-l00C.

3. The process of claim 2 wherein the temperature is about 25-50C.

4. The process of claim 1 wherein the ether has the formula I-ICCl ORwherein R is an organic group that is inert in the process.

5. The process of claim 1 wherein the sulfide has the formula R R CClSRwherein R and R are H or organic groups inert in the process and R is anorganic group inert in the process.

6. The process of claim 5 wherein R and R are H and R is alkyl.

7. The process of claim 6 wherein R is CH sulfide and the dichloromethylether are used in substantially equimolar amounts and the reaction isconducted at a temperature of about 0-l00C.

1. THE PROCESS OF MAKING AN A-CHLORO SULFIFE COMPRISING REACTING BYCONTACTING THE CORRESPONDING SILFOXIDE WITH A DICHLOROMETHYL ETHER. 2.The process of claim 1 wherein the reaction is conducted at about0*-100*C.
 3. The process of claim 2 wherein the temperature is about25*-50*C.
 4. The process of claim 1 wherein the ether has the formulaHCCl2OR2, wherein R2 is an organic group that is inert in the process.5. The process of claim 1 wherein the sulfide has the formulaR3R4CClSR5, wherein R3 and R4 are H or organic groups inert in theprocess and R5 is an organic group inert in the process.
 6. The processof claim 5 wherein R3 and R4 are H and R5 is alkyl.
 7. The process ofclaim 6 wherein R5 is CH3.
 8. The process of claim 6 wherein the etheris a dichloromethyl alkyl ether.
 9. The process of claim 7 wherein theether is dichloromethyl methyl ether.
 10. The process of claim 9 whereinthe Alpha -chloro-sulfide and the dichloromethyl ether are used insubstantially equimolar amounts and the reaction is conducted at atemperature of about 0*-100*C.